Catalytic membrane reactors based on oxygen-permeable membranes are recently studied for hydrogen separation because their hydrogen separation rates and separation factors are comparable to those of Pd-based membranes. New membrane materials with high performance and good tolerance to CO2 and H2S impurities are highly desired. In this work, a new membrane material Ce0.85Sm0.15O1.925-Sr2Fe1.5Mo0.5O6-delta (SDC-SFM) was prepared for hydrogen separation. It exhibits high conductivities at low oxygen partial pressures, which is benefit to electron transfer and ion diffusion. A high hydrogen separation rate of 6.6 mL cm(-2) min(-1) was obtained on a 0.5-mm-thick membrane coated with Ni/SDC catalyst at 900 degrees C. The membrane reactor was operated steadily for 532 h under atmospheres containing CO2 and H2S impurities. Various characterizations reveal that SDC-SFM has good stability in the membrane reactor for hydrogen separation. All facts confirm that SDC-SFM is promising for hydrogen separation in practical applications. (c) 2018 American Institute of Chemical Engineers